Preparation of fluorine-containing carboxylic acids



AUS 25, 1970 ATsUoKATsusx-HMA ETAL 3,525,758

PREPARATION OF FLUORINE-CONTAINING CABOXYLIC ACIDS Filed Feb. 5, 1965/A/ nauseas Mew/A (2.51)

Lon/E/I/THHTIo/v {mole/f) H WH H 6.00 Q FLE /G\b)4 @EEZ Erb l \/4.J .d cABC Cl n/vm/Tfrfmo/u (male/f) H m 6H 4 @m @6 F@ 6F \/M3 RFJP CEU DEUnited States Patent Oce 3,525,758 Patented Aug. 25, 1970 Int. Cl. C07c53/34 U.S. Cl. 260-408 r 4 Claims ABSTRACT F THE DISCLOSURE Aliphaticw,w di-(triiluoromethyl) peruorocarboxylic acids and salts, esters andamides thereof. The acids have the structural formula:

wherein n is 2 to 21.

Methods for preparing such compounds by oxidizing compounds having thefollowing structural formulae:

wherein Y is Br or l;

X1 and X2 are each H, F, C1, Br or I, but only one of X1 and X2 may beF;

X3 and X4 are each H, F, C1, Br, l, OH, R, OR, OCR, OOCR, ROH, COOR, orCOOH, R being an alkyl group having 1 to 3 carbon atoms;

X5 and X6 are each H, Cl, Br or I, but only one of X5 and X6 may be H;

m is an integer from 1 to 10; and

p is an integer from 2 to 3.

The acids and the derivatives have improved surface tension properties.

This invention relates to ilumine-containing compounds. Moreparticularly, the invention pertains to the aliphaticw,wdi(triuoromethyl)-peruorocarboxylic acids having a group of theformula attached to a terminal position. The invention further relatesto the method of manufacturing said carboxylic acids.

The experience and research of the present inventors in the productionof aliphatic peruorocarboxylic acids and the properties thereof haveshown that there are radical differences between the straight-chainperuorocarboxylic acids and the branched-chain pertluorocarboxylic acidshaving a group of the formula bonded to a terminal position, and thatthe latter excell much more compounds in utility than the former.

It is accordingly one object of this invention to provide a series ofuseful aliphatic w,u-di(trifluoromethyl)per fluorocarboxylic acidshaving as a side chain a triuoromethyl group attached to a terminalposition.

Another object of the invention is to provide aliphatic uw di-(triuorornethyl) peruorocarboxylic acids displaying a marked ability inliquid media to decrease the surface tension of said media to aconsiderable extent.

A further object of the invention is to provide aliphaticw,wdi(triuoromethyl)-peruorocarboxylic acids, the surface tension ofwhich is no more than, 18 dynes/cm. in the vicinity of the criticalmicelle concentration in aqueous media.

A still further object of the invention is to provide aliphatic was di(triuoromethyl) peruorocarboxylic acids which can be profitably employedas raw materials for the manufacture of useful Water and oil repellantsand surface active agents.

A still further object of the invention is to provide aliphaticw,wdi(uoromethyl)-peruorocarboxylic acids which can be employed asuseful intermediates for the production of various types offluorine-containing compounds.

A still another object of the invention is to provide a profitableprocess for the manufacture of aliphatic w,wdi (triuoromethyl)perfluorocarboxylic acids having the aforesaid characteristics.

Other objects and specic features of the invention will become apparentin view of the following:

The aliphatic w,w di- (triuoromethyl) perfluorocarboxylic acids of thisinvention are of the formula:

wherein nis an integer from 2 to 21.

The compounds of the aforesaid formula are:

Compound B.P. in O. Compound B.P. in O.

CFa 157 CFS 189.

CF(CF2):CO0H CF(CF2)4COOH CFa CF;

CF3 175 CF3 CF(CF3)3COOH CF(CF:)5COOH 205.

CF; CFa

CF3 218 CFs 315.

CF(CF2)|COOH CF(CF2)14COOH CF: CFa

CF; 233 CF1 240/50 mm. Hg.

CF(CF2)7COOH CF(CF2)15COOH CF3 CFB CF3 245 CFa 228/30 nlm. Hg:

CF (CFz)sCOOH CF (CFa)1|COOH CF: CF;

CFB 259 CF; 258/50 mm. Hgs

CF; CF;

C Fg 270 CF: 264/50 mm. Hg.

CF(CF2)10COOH \CF(CF3)1aCOOH C s CF1 CFS 282 OF5 268/50 mm. Hg.

CF(CFa)x1COOH CF (CFz)19COOH CF3 CF.

CFa 295 CFS 274/ mm. Hg.

CF(CF2)12CO0H CF(CF2)20COOH CF; CF;

C F3 305 CFB 284/50 mm. Hg.

CF (CFa)xaCOOH CF(CF2)21COOH CF; CFa

The compounds of the aforesaid formula in which n is from 2 to 6 areliquids at normal room temperature, whereas the compounds of saidformula in which n is from 7 to 21 are solids at normal roomtemperature. All of the compounds of said formula are acidic and excellin resistance to heat, chemicals and weather. Said compounds have aparticularly pronounced low order of surface tension in that theyexhibit no more than 18 dynes/ cm. lal: the vicinity of critical micelleconcentration in aqueous media.

Like the conventional straightchain aliphatic peruorocarboxylic acids,the branched-chain aliphatic w,w di-(trilluoromethyl)-peruorocarboxylicacids of this invention have a general tendency to decrease the surfacetension of liquid media in which they are employed with an increase inthe chain length of such branchedchain acids. As compared with theconventional straightchain aliphatic peruorocarboxylic acids,y however,the branched-chain w,w di (triuoromethyl)-peruorocarboxylic acids ofthis invention having theV same chain length or the same number ofcarbon atoms, as the convetional compounds exhibit a markedly low orderof surface tension. This outstanding feature of the invention is readilyapparent from a review of the attached drawings. FIG. 1 is a graph onwhich the concentration in mole/liter of water of various compounds isplotted against the surface tension properties of the resultingsolutions.

In FIG. 1, 1ines A, B, and C represent such plottings for the compoundCF, y omormooon y C Fa I of this invention, and conventional compoundsCF3 (CP2) BCOOH and CF3 (CF2)4COOH, respectively. FIG. 2 is a graph onwhich similar plottings are made for compounds D, E and F, which are thecompound C Fa A oFoFmoooH 4 C F 3 of this invention, and conventionalcompounds pounds A and D. Further, compounds A and D of this inventionalways provide a lower order of surface tension, particularly a.markedly lower order of surface tension in a concentration below thecritical micelle concentration, than the straight-chain compounds C andF, which respectively have the same number of carbon atoms as compoundsA and D and a longer chain length than compounds A and D.

Such phenomena as specified above indicate the possibility that thebranched-chain aliphatic w,wdi(triuoro methyl)-perliuorocarboxylic acidsof this invention and the salts, esters, amides, nitriles and polymersderived therefrom, to excell much more in water and oil repellency andsurface active properties than the corresponding straight-chainaliphatic perliuorocarboxylic acids and the derivatives thereof. Infact, the water and oil repel-I lency experiments performed by thepresent inventors showed a marked difference in such properties betweenthe two series of the compounds in question. For instance, anisopropanol solution containing 0.1 percent by weight of the chromiumcomplex of a compound of the formula CF (CFMCOOH CFB of this inventionimparts to gauze an ability to block the penetration of machine oil andliquid paraffin for more than 24 hours, whereas CF3(CF2)4COOH having thesame number of carbon atoms but a longer chain could not protect gauzefor no more than l() minutes when employed under the same conditions asspecified above, and CF3(CF2)3COOH having the same chain length couldnot even block the penetration of liquid paraffin when employed underthe same conditions as specified before. Such excellent water and oilrepellency can be secured by the aliphatic uw di (trifluoromethyl)perfluorocarboxylic acids of this invention when employed in the form of,not only chromium complexes, but as zirconium salts, aluminum salts, orpolyesters obtained by esterifying polyvinyl alcohol, or rubber-likepolymers prepared by polymerizing esters of any of the aliphaticperfluorocarboxylic acids of this invention and an unsaturated alcohol,such as allyl alcohol, or derived from unsaturated esters, such as ofthe formula wherein n is as defined before, q is an integer from 2 to 4,and R stands for a hydrogen or methyl group.

The aliphatic w,wdi(trifluoromethyl)-perfluorocarboxylic acids of thisinvention and the derivatives thereof, further, possess marked surfaceactive properties, exhibiting a pronounced ability for emulsifying, inaqueous media, polyfluorovinyl compounds, polyiiuoroalkenes and thepolymers thereof, so that the peruorocarboxylic acids of this inventionare very useful as agents for the emulsion polymerization of unsaturatedpolyuoro compounds as disclosed herein. For instance, as described inExample l below,

CF(CF2)4COON2\ 'of this invention provided a reaction speed and polymerconcentration far greater than the straight-chain CF3 2) COONa.

having the same number of carbon atoms but a longer chain, when employedas an emulsifying agent for polymerizing tetrafluoroethylene in aqueousmedia under irradiation with ionizing radiations. As an emulsifyingagent for such reactions, the carboxylic acids and the water-solublesalts derived therefrom of the formula M being sodium, potassium orammonium, and n' being an integer from 2 to 21, particularly from 3 tol0, are profitably employed. The compounds of said formula not -onlyhave pronounced emulsifying ability but also excell in resistance tochemicals, heat and weather, so that the aqueous emulsions of thetiuorine-containing polymers emulsified with `said agent are usefulcompositions having a wide range of application. For instance, theanionic compounds of the formula n being as defined before and r beingan integer from 1 to l2, and the cationic compounds of the formula/omcrnnooNmcHnqoomir ora c1- are all profitably employed as usefulsurface active agents.

The aliphatic w,w-di-(trifluoromethyl)-periiuorocarboxylic acids of thisinvention can also be employed in the form of the original carboxylicacid or an acid anhydride as a profitable accelerator for theesterification reaction or the polymerization reaction of silicones. Forinstance, the derivatives of the formula of this invention, n being asdefined before, are particularly useful as a cockroach attractant.

Thus, the aliphatic w,wdi(trifiuoromethyD-peruorocarboxylic acids andthe derivatives thereof of this invention are not only useful inthemselves but as intermediates for preparing water and oil repellants,surface active agents, anti-fouling agents, dyestus, insect attractants,insecticides, heat-proof resins and rubbers, and similar articles.

The aliphatic w,w-di(triuoromethyl)perliuorocarboxylic acids of thisinvention, further, possess lower melting points and highersolvent-solubilities than the straight-chain aliphaticperfluorocarboxylic acids having the corresponding number of carbonatoms, so that the compounds of this invention can be more easilyprocessed than the conventional carboxylic acids. For instance,

of this invention is in a liquid state at normal room temperature, sincethe melting point thereof is about -10 C., Whereas CF3(CF2)5COOH havingthe corresponding number of carbon atoms is in a solid state at normalroom temperature, the melting point thereof being 55 C.

Not only the aliphatic w,wdi(trifiuoromethyl)peruorocarboxylic acids ofthis invention but the derivatives thereof possess a high order ofsolvent-solubility. For instance, a polyester having an ester value ofpercent and which is obtained by esterifying in dimethyl formamide apolyvinyl alcohol having a polymerization degree of 500 and asaponiiication value of about 100 percent with an acid chloride of ofthis invention, can be easily dissolved in acetone ortriuorotrichloroethane, producing a homogeneous solution, whereas thepolyester having an ester value of 90 percent and which is preparedunder the same conditions as described before with CF3(CF2)6COOH, whichhas the corresponding number of carbon atoms, is insoluble in acetoneand difficult to dissolve in tritluorotrichloroethane, requiring a longperiod of stirring before being completely dissolved therein. Thesephenomena also verify the fact that the aliphaticw,wdi(triiluoromethyl)per uorocarboxylic acids of this invention and thederivatives thereof can be easily employed and possess a wide range ofapplication.

As stated before, the aliphatic w,wdi(triuoromethyl) peruorocarboxylicacids of this invention display a gradual decrease in surface tensionproperties with an increase in the chain length of the acid employed.This ability, however, almost attens out when the value of n reaches ormore, and the synthesis of such compounds becomes increasingly diicult.The most desirable compounds of this invention, accordingly, are thosecompounds of the aforesaid formula having n in the range of from 3 to10.

The aliphatic w,wdi(triuoromethyl)-peruorocarboxylic acids of thisinvention are obtained by oxidizing any of the compounds of thefollowing formulas:

CFs

CFa

CF(CFaCF2)m(CH-=CX5)X CF (IV) wherein Y is -Br or -I; X1 and X2 arerespectively --H, -F, -Cl, -Br, or -I, said X1 and X2 being mutuallyexclusive in terms of -F; each of X3 and X4 is -H, -F, -Cl, --Br, -I,-OH, -R, -OR, -OCR, -OOCR, -ROH, -COOR, or -COOH, R being alkyl havingfrom 1 to 3 carbon atoms; X5 and X6 respectively stand for -H, -Cl, -Br,or -I, said X5 and X6 being mutually exclusive in terms of -Hg m is aninteger from 1 to l0; and pis an integer from 2 to 3.

Representative compounds of lFormulas I to IV are as follows,

(III) being designated by Rf for brevitys sake.

(1) Compounds of Formula I:

(2) Compounds of Formula II: RfCH2CHClI RfCH2CH(CH3)IBr RfCHzCHgBrRfCHClCHClI lRICHZCHIOOCCHa RfCHgCHICOOCH;i RCHZCHZI RCHZCHICHZOHRfCHClCFClBr (3) Compounds of Formula III: RfCH=CH2 RfCH=CHCOOHRfCH=CHCl RCH=CHCOOCH3 RCH=CFC1 RCH=CHOOCCH3 (4) Compounds of FormulaIV: Rf(CH=CH)3Cl Rf (CH=CC1) 2C1 As an agent for oxidizing the compoundsof Formulas I to IV, there are employed potassium dichromate and similardichromates, potassium permanganate and similar permanganates, fumingsulfuric acid, or oxygen, Suitableoxidizing conditions should bedetermined in view of the species of the starting material and of theoxidizing agent to be employed. In the following are described the mostdesirable conditions for said oxidization re'actions which areillustrative only and not limiting the scope and extent of the presentinvention.

(A) OXIDATION OF THE COMPOUNDS OF FORMULA I The most desirable oxidizingagent for the oxidation of the compounds of Formula I is oxygen orfuming sulfuric acid.

(a) Oxidation with oxygen- The starting material is oxidized with oxygenemployed in the order of from 3 to 7 moles per mole of the startingmaterial under the irradiation of light, particularly visible light, orultraviolet rays. The initial reaction pressure ranges from normalatmospheric pressure to 20 kg./cm.2, and the reaction temperatureemployed is from normal room temperature to about 50 C. There may beadded chlorine, iodine or steam as an accelerator in the order of from/lo of a mole to equimolar amounts. As a source of oxygen oroxygen-containing gases, such as air, are profitably employed.

(b) Oxidation with fuming sulfuric acid.-In this instance, there isemployed a 10 to 70 percent fuming sulfuric acid in the order of from 2to 6 times the original weight of the starting material in terms of S03.The reaction is carried out at a temperature ranging from about to about170 C. under normal atmospheric pressure, or under increased pressure,where necessary.

(B) OXIDATION OF THE COMPOUNDS OF FORMULAS II TO IV 11n addition to theaforesaid processes described under (A(a)) and (A(b)), there areemployed as an oxidizing agent in the instant oxidation reactionspermanganates or dichromates in amounts ranging from 1.5 to 5 moles permole of the starting material in conjunction with an acid, such asconcentrated sulfuric acid or glacial acetic acid, or an aqueoussolution of alkali salt, such as sodium hydroxide or potassium hydroxidein the order of from an equimolar amount to l0 moles per mole of saidoxidizing agent. The reaction is performed at a temperature ranging fromnormal room temperature to about C. under a pressure of from normalatmospheric pressure to the vapor pressure of the compound to beoxidized at the reaction temperature.

(C) SYNTHESIS OF THE STARTING MATERIAL CNCFZCFQMY or; wherein Y and mare as defined before.

(l) Synthesis of the compounds of Formula I.-The compounds of Formula Iare manufactured by the addition reaction of a compound of Formula V anda compound of the formula CF2=CX1X2, X1 and X2 being as defined before,in the following manner:

(2) Synthesis of the compounds of Formula II.-The compounds of FormulaII are produced by the addition reaction of a compound of Formula V anda compound of the formula CHF-C'XBX, X3 and X4 being as defined before,in the following manner:

(3) Synthesis of the compounds of Formula IIL- The compounds of FormulaIII are synthesized by the addition reaction of a compound of Formula Vand acetylene or by dehydrohalogenation (-HY, Y being as defined before)of a compound of Formula Il in the following manner:

CF(F20I).(CH=CX)XI CF: (X)

Of the above reactions, the addition reactions of Equations VI, VII andVIII are carried out radically by the action of light, heat or a freeradical initiator. An increase in the amount of the unsaturated compoundemployed generally promotes telomerization or similar phenomena. Inorder to improve the yield of the addition product without producing anyundesirable by-products, the amount of the unsaturated compound to beemployed should be carefully determined in View of the properties of thecompound of Formula V to be employed therewith. Said amount also varieswith the degree of self-polymerization potential. For instance, acompound having a high order of self-polymerization potential, such asCHFCHI, CH2=1CHOOOCH3, CHZIICH CH2=CHCOOCH3 or CHECH, is preferablyemployed in the order of from 0.1 to 0.9 mole per mole of the compoundof Formula V. In order to raise conversion levels, such unsaturatedcompounds are added not in a single charge but incrementally orcontinuously. An unsaturated compound having a low order ofself-polymerization potential, such as CHClrCHCl, CF2=OC12 or CF2=CHF isemployed in an equimolar amount or may be added in excess in relation tothe compound of Formula V.

When light is employed at the initial stage of reaction, visible lightor ultraviolet rays is preferably employed at a temperature ranging fromnormal room temperature to about c7 C. The reaction pressure varies withthe vapor pressure of the stock material. For instance, CH2=CHC1,CHFCHZ, CH.= CH or CFZ=CFH is preferably allowed to react in a closedvessel under autogenous pressure. There may however be employed anincreased pressure ranging from 1 to 50 kg./cm.2. A reactant having ahigher order of boiling point is employed in an open vessel by coolingunder a reflux condenser. When heat is employed to initiate thereaction, the reaction is preferably carried out in a closed vessel at atemperature ranging from to 250 C. or thereabout. When a free radicalinitiator is employed, the reaction is desirably carried out at atemperature ranging from normal room temperature to about 150 C. under apressure from l to 50 kg./ :m.2 The free radical initiator employed inprocesses of this invention tertiarybutylhydroperoxide,ditertiarybutylperoxide, benzoylperoxide, diisopropylperoxydicarbonateand similar organic peroxides, or azobisisobutyrontrile and similarorganic azo compounds.

The dehydrohalogenating reaction of Equations IX and X can be carriedout in various Ways. Particularly, said reaction is desirably performedwith an alkali metallic compound, such as potassium hydroxide, sodiumhydroxide or sodium carbonate, or with an alkali metal, such as metallicsodium, in a saturated alcohol, such as methanol, ethanol or isopropylalcohol, in an open or a closed vessel at a temperature ranging fromnormal room temperature to about 100 C. Said dehydrohalogenatingreaction, however, requires no particular reaction conditions. Anyconventional method Imay be profitably employed.

m and Y being as defined before, and which are employed as a startingmaterial for the production of the compounds of Formulas I to IV aresynthesized by the reaction of a periluoroisopropyl halide of theformula CFY Y being as defined before with tetrauoroethylene by variousprocedures. It is desirable, however, to carry out the reaction with theaid of irradiation by ionizing radiation, a method which was devised bythe present inventors and disclosed in their Japanese patent applicationNo.

(D) SYNTHESIS OF 1 1 6,569/ 1964. Alternatively, the reaction may beprofitably carried out in the presence of a free radical initiator, amethod which was also devised by the present inventors and disclosed inour Japanese patent application No.

The irradiation sources employed in thev former method include a-rays,-rays, y-rays, X-rays,'neutron rays, proton rays, deutron rays andsimilar ionizing radiations, o'f which fy-rays, particularly y-'raysemitting'froinz Co60 are most preferable. The dosage rate ranges from 1X102 r./hr. to 1 106 r./hr., particularly from 1 103 r./hr. to 1 105r./hr., preferably withinthe total dosage rangeof from 1 103 to l 106 r.The reaction temperature and reaction pressure cau be varied over a Widerange. Namely, the reaction temperature to be used ranges from about thetemperature of the liquid nitrogen employed to 'about Y 150 C.,particularly from 90 to 100 C. Either reduced or elevated pressure maybe used, but the reaction satisfactorily proceeds under normalatmospheric pressure or a pressure amounting to about 50 kg./cm.2. Thestarting peruoroisopropyl halide is preferably employed in the order offrom 1 to 10 moles for 10 to 1 moles of the tetrauoroethylene to beemployed therewith.

The free radical initiator employed in the latter of the aforesaidmethods includes benzoylperoxide, ditertiarybutylperoxide,tertiarybutylperbenzoate, tertiarybutylhydroperoxide and similar organicperoxides, and azobisisobutyronitrile and similar organic azo compounds.The amount of said initiator to be employed ranges from 0.05 to 10percent by weight, particularly from 0.5 to 5 percent by weight, inrelation to the stock material. The reaction conditions vary with theproperties of the initiator to be employed, but the reaction isprofitably carried out at a temperature ranging from 50 to 200 C. undera pressure of from 5 to 200 kg./cm.2. In this reaction, the startingperfiuorosopropyl halide is employed in amounts of the order of from 1to 5 moles for 5 to 1 mole of tetrauoroethylene, preferably from 1 to 3moles per mole of tetrafluoroethylene. Whether ionizing radiations orfree radical intiators are employed, the reaction can be satisfactorilycarried out batchwise or discontinuously or continuously.

Thus, the desired aliphatic ,w-di-(triuoromethyl)-peruorocarboxylicacids of this invention can be easily obtained as notedabove fromintermediates prepared by the reaction of the readily availableperiluoroisopropyl halides with tetrauoroethylene, thus producing thecompounds of Formula V, from which the compounds of Formulas I to IV canbe prepared.

In the following are described the preferred methods employed in thisinvention for the production of the compounds of the formula m being asdefined before:

(1) There were placed in a 50G-cc. Hastelloy-C agitator-type autoclave,Hastelloy being a trade name, Union Carbide Corp., U.S.A., 185 grams(0.625 mole) of peruoroisopropylodide of the formula CFa CFI

Ca 0.7 gram of tertarybutylhydroperoxide, and 3.3v grams ofditertiarybutylperoxide. After freezing the mixture with liquid air, theair present in the autoclave was evacuated under reduced pressure. Therewere then added 35 grams of tetrauoroethylene, and the mixture wasagitated while passing steam therethrough. The reaction temperature roseto 100.5 C. and the maximum pressure reached 20.5 lig/cm.2 10 minutesafter application of the steam heating, but the pressure startedgradually falling thereafter. When the pressure fell to 6 kgJcm.2 5hours afterapplication of the steam heating, agitation and steam heatingwere suspended'and the autoclave was cooled' with water. Then thepressure fell to almost 0 kg./cm'.2, producing 217 gr rrns vof reactionproducts. When the lreaction products wereI fractionally'distilled,therewere'obtained:

Grams, B.P. in C./

moles mm. Hg

Unreacted /O FI 139. 6(0. 472) CF(CF2GF2)I 20.9(0.'0`528) se to88.5/760.

CFa"

CF(CF2CF2)2I 25. 3(0.'o510) 74 to 76/92 to 94.'

CF C@ 0F(CF2CF2)3I 13.1(0.0264) 69 to 72/10 to 11,5.

CF. Ca

CFCFaCFmI 10. 5(10. 01,76) 91v to 9 1.5/4.5 to 5.o.

CFS

CFa

CF(OF2CF)5I v 4. 2 125 to 12s/4.5 to 5.0.

Others 3.4

Conversion f Percent Perfluoroisopropyliodide 24.5 Tetrai'luoroethylene96.1

(2) In accordance with the procedure as described in the formerinstance, there were placed in a 1liter Hastelloy-C autoclave 296 grams(1.00 mole) ofl peruoroisopropyliodide, grams (1.00 mole) oftetrauoroethylene, and 1.9 grams (0.048 mole) of azobisisobutyronitrile,and the mixture was reacted at 100 to 110 C. for 10 hours. When theresulting reaction products were frac- (3) There were placed in aISO-cc. pressure glass cylinder 242.4 grams (0.819 mole) ofperuoroisopropyliodide and 16.4 grams (0.164 mole) of tetrauoroethylene,and the mixture was frozen with liquid nitrogen. After the cylinder wasclosed airtight,1the air present in the cylinder was evacuated. Thecylinder was then separated from the liquid nitrogen and graduallywarmed atl roo'rrl temperature with stirring to thoroughly mixthe stockmaterials. Whenthe temperatureof themixture had risen to about normal`'room temperature and the pressure to 1.6

lig/cm?, the pressure cylinder was placed 20 cm. apart from a2,000-curie Coso source, and the mixture was subjected for 2 hours tothe irradiation of 'y-rays emitting from said radiation source. Theresultant products contained when fractionally distilled:

\CF(CF2CF3)I 4.4 grams 13.1. 30 C./92.5 mm. Hg. et.

\CF(CF3CFQ)3I 0.6 grams. B.P. 29 C./37.5 mm. Hg. C 143 ConversionPercent Perfluoroisopropyliodide 1.50 Tetrauoroethylene 8.24

For a fuller understanding of the principles of this invention, thereare provided in the following the preferred examples which areillustrative only and not limiting in any sense of the scope and extentof the invention.

EXAMPLE 1 ln a 150-cc. Hastelloy-C autoclave there were placed 150 grams(0.303 mole) of In a 1D0-cc. four-neck ask, in the next step, there wereplaced with stirring 18 grams of potassium hydroxide and 20 grams ofethanol. After complete agitation, there were added portionwise 68 gramsof the aforesaid crude CFS CFs while maintaining the reactiontemperature at around 50 to 60 C; by cooling the rising temperature dueto the exothermic reaction. After such addition was completed, thetemperature was raised to 80 C. and the agitation was continued for anadditional lhour.

The resulting reaction product was thenpoured into 200 cc. of water.After separation of the oil phase, the liquid phase was extracted withchloroform. The resultant extract and the oil phase were then dehydratedtogether with magnesium sulfate anhydride and fractionally distilledafter removing the chloroform, producing 49.5 grams (0.125 mole) f CFaCF oF2oFmCH=oHz CF: Yield was 96.2 percent on a mole basis.

Synthesis of 48 grams (0.121 mole) of the product thus obtained werethen stirred at to 135 C. for 8 hours with a mixture of 74 grams ofpotassium dichromate, 162 grams of concentrated sulfuric acid and 58grams of distilled water, and steam-distilled. The extract was thenneutralized with a 5 percent potassium hydroxide aqueous Solution,evaporated and dried. The solid residue thus separated was placed inexcess concentrated sulfuric acid and distilled under reduced pressure,producing 48 grams of Analysis-Calci (percent): C, 23.2; P, 68.8; H,0.24. Found (percent): C, 23.0; F, 69.1; H, 0.27.

Other properties: M.P. 10.5 to 11.0 C.; 111,25, 1.3134; d425, 1.76g./cc.

The compound thus prepared was neutralized with sodium hydroxide andrecrystallized with toluene-n butanol anhydride, producing dried whichdisplayed a marked effect on the emulsification polymerization oftetrafluoroethylene in aqueous media.

Namely, there were placed in a Z-Iiter agitator-type autoclave 0.3percent by weight of said and 6 percent by weight of n-cetane as astabilizer in 800 cc. of deoxidized distilled water. After evacuatingthe air present in the autoclave, tetrauoroethylene gas was introducedto pressurize the autoclave to thelevel of about 6 14g/cm.2 and themixture was completely agitated. The mixture was then subjected toirradiation of ry-rays emitting from a 2,000-curie Co60 source. As thepolymerization reaction progressed polymerization, the reactiontemperature gradually fell. To compensate for this drop in thetemperature, additional tetrauoroethylene was supplied to keep thereaction pressure at the level of about 6 kg./cm.2. After sustaining anirradiation dosage of 8X104 r., the mixture was allowed topost-polymerize for as additional 30 minutes. The resultant dispersionhad a polymer concentration of 28.7 percent by weight, and the maximumreaction velocity was 4.1 moles per liter per hour, whereas whenCF3(CF2)6COONa was employed as an emulsifying agent as a control underthe same condij tions there was produced a dispersion having a polymerconcentration of 20 percent by weight with the maximum reaction velocityreaching no more than 3.0 moles per liter per hour.

EXAMPLE 2 CFa CF(CF2)2COOH CFa Synthesis of In a SOO-cc. autoclave therewere placed grams (0.392 mole) of acted acetylene, and the reactionmixture was fractionally distilled, producing 92.5' grams (0.219 mole)of CFS CFCFZCF2CH=CHI CFB 67.7 grams of runreacted ons CFCF2CF2I CFaEXAMPLE 3 CFa CF(CF2)uCOOH CFa In a 150-cc. Hasteloy-C autoclave therewere placed 150 grams (0.252 mole) of v12.5 grams (0.200 mole) of vinylchloride, and 1.9 grams of azobisisobutyronitrile, and the mixture wasfrozen with liquid air. After evacuating the air in the autoclave, themixture was agitated at 100 to 110 C. for 90 minutes while heating withsuperheated steam. The reaction pressure fell from an initial value of7.8 kg./cm.2 to 2 kg./cm.2. When further cooled to about roomtemperature, the pressure in the autoclave fell to an order level lowerthan normal atmospheric pressure, and no unreacted vinyl chlorideseparated out. When the resultant liquid reaction mixture of 162.1 gramswas fractionally distilled,

Synthesis of vthere were obtained 38.1 grams (0.064 mole) of unreacted118.5 grams (0.180 mole) of CF CF2CF2 3CH2CHC1I C Fs and 5.4 grams ofother substances. Yield was 95.8 percent by mole.

Conversion:

74.6 percent on a mole basis'.

Vinyl chloride: 100 percent on a mole basis.

In the next step, there were placed in a 300-cc. fourneck ask 118.2grams of the resultant I v CFa oFwFzoFmCHzCHCII 1'44 'gansf'pota'ss'iindichimafe,and 11'3 grains of distilled Water. There were thenadded portionwise with stirring 3.12 grams of concentrated sulfuric acidfor 2 hours. Such a very active exothermic reaction took place, that theexothermic heat was controlled at the initial stage.` After thecompletion of such addition, agitation was continued for an additional 3hours at a reuxing tern- Peratilref VWhen ha raion was O Hltsld.Y themixture was steam-distilled, neutralized with diluted sodium hydroxide,evaporated to remove the water, extracted with ethanol to remove thesodium iodide, and filtered. The ethanol being removed,the ltrates weredistilled with concentrated sulfuric acid Vemployed in an arnountl ofabout 2.5 times the original weight of the ltrates, producing 81.1 gramsof v CFa omo'rzormooon CFa of B.P. 74 to 76 C./1.5 to 2.5 mm. Hg.

Arralysis.-Calcd. (percent): C, 23,34; F, 70.23; H, 0.19. Found(percent): C, 23.51; F, 69.88; H, 0.21.

Infrared absorption showed u c=0 at 5.67. Yield was 88.2 percent on amole basis.

EXAMPLE 4 Ca synchesisof o F (orme o 0H C Fs f In a .SOO-cc. stainlesssteel autoclave there were placed 248 grams (0.5 mole) of f CFSCF(CF2CF2)2I CFa and 3.4 grams of ditertiarylautylperoxide, and themixture was frozen with brine cooled with Dry Ice. After evacuating theairin the autoclave with nitrogen gas and then with CFg'rCFCl gas, therewere added 46.6 grams (0.400 mole) of CFFCFCl, and the mixture wasagitated carefully at.120 to 130 C. A violent reaction took place duringthe initial 30 minutes after the application of agitation, but thereaction gradually slowed down. When the reaction pressure fell to aconstant level of 2.2 kg/cm..2 3.5 hours after the application ofagitation, the reaction mixture was cooled to normal room temperaturewith cold water. There were thus obtained 295 grams of a liquid productcontaining almost no unreacted CFZ=CFCL The product thus obtained wasthen placed in a two-neck ask and fractionally distilled while passingnitrogen gas through the capillary tubes', producing 126.8 grams (0.256mole) of unreacted CFa omorzormr CF@ of B.P. 75 to 76 C./4.0mrn.1Hg,'90.6 grams (0.148

17 and 26.9 grams of other substances, totaling 156.6 grains in all.Conversion of concentrated sulfuric acid, there were obtained 98.2 gramsof CF, CF1

CF(CF'.CF2)2I CF(CF2CF2)4COOH CFE 5 cri was 48.8 percent on a molebasis, and yield of CFa of B.P. 70 to 75 C./1.0 to 1.5 mm. Hg.

Analyss.-Ca1cd. (percent): C, 23.45; F, 71.18; H, CFWFZCMCFFC 0.16.Found (percelen c, 23.89; F, 70.09; H, 0.14. OF5 Molecularweight.-Calcd.: 614.18. Found: 612.5. was 60j percent on a mole basisYield: 82.5 percent on a mole basis. 90 grams (0.147 mole) of theresultant EXAMPLE 6 una CF@ CF(CF2CF2)2CF2CFC1I Synthesis ofCF(CF2)2COOH CFa CFs were then oxidized with fumng sulfuric acid at 150C. In a 500ML 4 neck ask in which the air was comfor 10 hours, and ih@resultant 20 pletely replaced with nitrogen gas there were placed GFS396 grams (1.00 mole) of \oF(cFiCFi 2oriooF CFS CF: CFCFzCFzI washydrolyzed, producing CFB Op, 86 grams (1.00 mole) of purified vinylacetate, and 1.2 grams of azobisisobutyronitrile and the system was/CNCFFZMCFZCOOH heated at 60 to 75 C. for 6 hours. There were then CFfurther added 39.6 grams of of B P. 75 to 76 C./3.5 to 4.0 mm. Hg.Infrared analysis 30 CF! indicated ilczat 5.66. CFC? CF I EXAMPLE 5 2 2CF: CF 112 f if'b "1 drh an grains o azo isiso utyromtri e, an e mixtureSynthesis 0f CF(CF2)5COOH 35 was heated at 75 to 85 C. for 3 hours. Whenunreacted F 210 ,gi-5ms (030251015) of C CFCFRCFBI CF:

onronnir CF CF; and vinyl acetate were separated, there were obtained419 grams of crude C F H O I. were reacted Wlfh 14 grams (025,0 mole) 0fAnalysis-calca. ipicnti: C, 22.4; F, 43.3; r, 26.4; and grams Ofdltel'tlalyblltylpel'x H 0.21. Found (Percent): C, F 42.1. I 26.9. ideat 120 to 130 C. for 4 hours. After separating 2.0 5 Hy 026l grams @036mole) 0f Dreamed CHZZCHCH2CH3 and 400 grams of the crude product thusobtained were 66.8 grams (0.096 mole) 0f unfeacted reacted with 93 gramsof potassium hydroxide in 100 cc. CFG of ethanol, and the mixture waspoured into 600 cc. of Water, extracted with chloroform, dried withmagnesium CMCFFI sulfate anhydride, and heated to expel the chloroform.CF;i The brownish liquid residue of 297 grams thus obtained a was placedin a 2-liter 4-neck flask and oxidized with there were obtained 0.194mole of a 1:1 molar addition stirring with 700 grams of potassiumdichromate and product and 9.2 grams of other substances. Conversion of1,700 grams of Concentrated sulfuric acid in 567 grams CF of distilledWater at 120 to 135 C. for 8 hours. The 3 resultant mixture was thensteam-distilled, neutralized om /CFtC F20 F041 with 5 percent potassiumhydroxide, and heated to dispel and CHFCl-ICI-IZCHa were respectively68.2 percent on a mole basis and 85.6 percent on a mole basis. Yield ofthe 1:1 molar addition product was 94.2 percent on a mole basis.

With the resultant 1:1 molar addition product there were then reactedwith stirring 260 grams of sodium permanganate and 1,500 grams ofglacial acetic acid at 100 C. for l0 hours. After decoloring theresulting product with sulfurous acid gas, the acetic acid was removedby distillation, and the separated solids were placed in 10 percentH2804 and continuously extracted with ether. To the resultant ethersolution there was added methanol in a quantity of about 2 times theoriginal volume of ether, and the mixture was carefully neutralized witha 20 percent sodium hydroxide aqueous solution, evaporated, and dried,producing 108 grams of light brownish solids. When fractionallydistilled with the water, producing 273 grams of light yellowish powder.When fractionally distilled with concentrated sulfuric acid underreduced pressure, there were obtained 99.0 grams of CFCFaCFzCOOH EXAMPLE7 CFS Synthesis o! In a 150-cc. pressure glass cylinder were placed 89.8

grams (0.20 mole) of CFS v of B.P. 51 to 52 C./60 mm. Hg and 9.7 grams(0.10 mole) of cis-1,2-dichloroethylene, and the mixture was frozen withliquid air. After closing the cylinder airtight, the air present wasevacuated, and the temperature was gradually raised with stirring toallow the two ingradients to mix thoroughly. When the temperature wasraised to about room temperature, the cylinder was placed cm. apart froma 2,000-curie C06o source and subjected for 3.5 hours to irradiation ofy-rays emitting from said source. Fractional distillation of theirradiated sample produced a 1:1 molar addition product (yield: 21.5percent on a mole basis) and 1:2 molar addition product (yield: 10.3percent on a mole basis).

Analyss.-Calcd. for C9F15Cl2BrH2 (percent): 19.8; F, 52.2; Cl, 13.0; Br,14.6. Found (percent): 20.2; F, 51.3; Cl, 13.1; Br, 14.1.

Analyss.-Calcd. for C11F15Cl4BrH4 (percent): 20.5; F, 44.3; Cl, 22.1;Br, 12.4. Found (percent): 20.4; F, 43.1; Cl, 23.8; Br, 11.7.

When grams of said CFa CF(CF2CF2)2CHC1CHC1Br were oxidized withpotassium chromate, concentrated sulfuric acid and distilled water asdescribed in Example 1, there was obtained the desired CF(CF2OF2)2CO0HCFa in a yield of 84.7 percent on a mole basis.

EXAMPLE 8 CFa In a SOO-cc. stainless steel autoclave were placed 198grams (0.500 mole) of Synthesis of 3.4 grams of ditertiarybutylperoxide,and the mixture was frozen with brine cooled with Dry Ice. Afterreplacing the air in the autoclave with nitrogen gas, there were added46.6 grams (0.400 mole) of CFZCFCl. The mixture was then carefullywarmed and stirred at 120 to 130 C. A violent reaction took place forthe initial 30 minutes after the application of stirring. But thereaction gradually slowed down thereafter, and the pressure fell to theconstant level of 2.2 kg./cm.2 3.5 hours after the application ofstirring. When the resultant mixture was allowed to cool to normal roomtemperature, there were obtained 245 grarns of a liquid reaction mixturecontaining almost no unreacted CF2CFC1. Fractional distillation of themixture produced 81.2 grams (0.205 mole) of CFS CF(CF2CF2)I CFs 130grams (0.254 mole) of CFa CF CF2CFZCFQCFC11 CMCFQSCOF CFa of B.P. 68 to70 C. in a yield of 71.3 percent on a mole basis and having an intensevc=0 infrared absorption at 5.27, 10.5 grams (0.0205 mole) of unreactedand 2.1 grams of other substances. Conventional hydrolysis of 10 gramsof said reaction product produced CFa CF(CF2)3COOH CFs of B.P. 67 to 70C./10 mm. Hg in a yield of 93.8 percent on a mole basis.

While the invention has been described with particular reference tospecific embodiments, it is to be understood that it is not to belimited thereto but is to be construed rather broadly within the scopeand extent of the appended claims.

We claim:

1. A method of preparing an w,wdi(triiluoromethyl) pertluorocarboxylicacid of the formula:

oFwFmCooH CF3 wherein n is an even integer from 2 to 20, which comprisesoxidizing with at least one member of the group consisting of alkalimetal chromate, alkali metal permanganate, fuming sulfuric acid andoxygen, a compound selected from the group consisting of the compounds of the formula:

wherein Y is a member selected from the group consisting of Br and -I;X3 and X4 are each a member selected from the group consisting of -H, P,-Cl, -Br, -I, OH, -R, OR, -OCR, -OOCR, -ROH, -COOR and -COOH, R beingalkyl having from 1 to 3 carbon atoms; and m is an integer from 1 to 10.

2. A method of preparing an w,wdi(triuoromethyl) peruorocarboxylic acidof the formula:

c Fa

or (orancoon wherein n is an even integer from 2 to 20, which com!prises oxidizing with filming sulfuric acid at a temperaf.

ture of from 90 to 170 C., a compound selected from the group consistingof the compounds of the formulas:

wherein Y is a member selected from the group consisting of -Br and -I;X3 and X1 are each a member selected from the group consisting of H, -F,-Cl, Br, -I, -Ol-I, --R, -OR, OCR, --OOCR, -ROH, -COOR and -COOH, Rbeing alkyl having from 1 to 3 carbon atoms; each of X5 and X6 standsfor a member selected from the group consisting of -H, -Cl, Br, and -Lsaid X5 and XG being mutually exclusive in terms of -H; m is an integerfrom 1 to 10; and p is an integer from 2 to 3.

3. A method according to claim 2 wherein said compound has the formula:

4. A method according to claim 2 wherein said compound has the formula:

CF(CF2CF2).(CH=CX)DX6 References Cited UNITED STATES PATENTS LORRAINE A.WEINBERGER, Primary Examiner 0 P. I. KILLOS, Assistant Examiner U.S. Cl.X.R.

